A dark sky typically refers to a night time sky where numerous stars are visible, unobstructed by artificial light and/or cloud cover. Outdoor light pollution is generally described as the inefficient use of light emissions. Misdirected or un-channeled light extends from lamp assemblies in the horizontal and vertical directions; therefore resulting in artificial illumination of the night sky.
For indoor lighting fixtures, lampshades are often used to concentrate light in a particular direction, and to shield glare from ones eyes. Lampshades enhance our ability to see objects through light concentration and glare reduction. However, this basic concept is often not incorporated into many of our outdoor lighting fixtures. The reason for the lack of light concentration on outdoor lighting fixtures is mainly because traditional thinking reasoned that the installation of more outdoor lighting fixtures will make an area safer.
As our population increases and land development continues, many homeowners, city planners, and architects continue the unnecessary installation of multiple outdoor lighting fixtures for the illumination of streets, parking lots, and buildings. Therefore, as more light fixtures are installed, the night is slowly being turned into day, without calculating the consequences of light pollution.
The ramifications of light pollution include: economic losses, scientific impacts on both amateur and professional astronomers, and visual impairment. First, the unwarranted generation of electricity to produce over-illumination results in economic loss to homeowners and businesses. Next, illumination of the dark skies limits the ability of astronomical observatories to view celestial objects at night. Lastly, glare emanating from light fixtures drastically reduces visual acuity.
As stated above, traditional thinking supported the position that safety would be enhanced with increased outdoor lighting fixtures in a given area. However, more recently, traditional notions have been criticized, and progress is being made to change the former concepts. Mainly, this criticism points to the negative impacts of light pollution and the ability to illuminate designated areas by light concentration rather than the number of lights. As these notions have become more main stream within urban planning and development circles, a continually need has arisen for improving technologies for directing light emitting from lighting fixtures, for improving the overall performance of outdoor lighting, and for simultaneously reducing light pollution.
While there have been numerous prior attempts at controlling the direction of light from lamps, they have consistently been costly and complicated to manufacture, assemble, package, and use, and have not been easily adapted to work with a large number of different light fixtures. Examples of such prior assemblies are disclosed, for example, in the following U.S. Pat. No. 1,696,875 to Andersen; U.S. Pat. No. 1,755,737 to Kesselring; U.S. Pat. No. 2,134,788 to Hitner; 2,907,873 to Smith; and U.S. Pat. No. 5,329,438 to Thompson, the disclosures of which are hereby incorporated herein by reference.
Consequently, there is a continuing need to provide a light-directing assembly which can be used for new light fixtures and retrofitting existing light fixtures which improves quality of lighting, not quantity.